ARCHITECTURE OF THE BONES OF THE SKELETON. 273 



The Hip Bone. As a flat bone the os coxae consists of spongy tissue between two com- 

 pact external layers. These, latter vary much in thickness, being exceptionally stout along 

 the ilio-pectmeal line and 



the floor of the iliac fossa 

 immediately above it. 

 The gluteal aspect of the 

 ilium is also formed by 

 a layer of considerable 

 thickness. The spongy 

 tissue is loose and cellular 

 in the thick part of the 

 ilium and in the body 

 of the ischium ; absent 

 where the floor of the 

 iliac fossa is formed by 

 the coalescence of the 

 thin dense confining 

 layers ; fine grained and 

 more compact in the 

 tuberosity of the ischium, 

 the iliac crest, and the 

 floor of the acetabulum, 

 in which latter situation 

 it is striated by fibres 

 which are directed radi- 

 ally to the surface 

 again being crossed at 



TROCHANTERIC FOSSA 



POSTERIOR SURFACE 



OF NECK 



Base of trochanter minor 

 cut through 



GREATER 

 TROCHANTER 



Interior of tro- 

 chanter major 

 containing loose 

 spongy tissue 

 (scraped away) 



Compact tissue 

 with dense core 

 forming the 

 calcar femorale 



Space containing loose spongy 

 tissue (scraped away) between the 

 calcar and the base of the tro- 

 chanter minor 



POSTERIOR SURFACE 



OF NECK 



of that hollow, these 

 right angles by others 



which are arranged circumferentially. This spongy 

 tissue forms a more compact layer over the surface 

 of the upper and posterior portion of the acetabular 

 articular area. The bottom of the floor of the acetab- 

 ulum varies in thickness ; in most cases it is thin, 

 and in exceptional instances the bone is here deficient. 

 The same condition has been met with in the iliac 



FIG. 278. DISSECTION SHOWING THE CALCAR 

 FEMORALE. 



A slice of bone has been removed from the pos- 

 terior aspect of the proximal part of the shaft 

 of the femur, passing through the trochanter 

 major superiorly and the trochanter minor 

 inferiorly and to the medial side. The 

 loose spongy tissue has been scraped away, 

 leaving the more compact tissue with the 

 dense core forming the calcar femorale. By 

 a similar dissection from the front the an- 

 terior surface of the calcar may be exposed. 



ANTERIOR fossa, where absorption of the thin bony plate 

 has taken place. 



The Femur. The body has a medullary 

 cavity which reaches the root of the lesser 

 trochanter proximally. Distally it extends to 

 within 3^ inches of the distal articular surface. 

 In. the proximal half the outer compact wall is 

 very thick, but distal to the middle of the body 

 it gradually thins until it reaches the condyles, 

 over which it passes as a thin, hardly definable 

 external layer. Proximally, it is especially 

 thick along the line of the linea aspera, and 

 here the large nutrient canal may be seen pass- 

 ing obliquely towards the proximal end in the 

 substance of the dense bone for the space of two 

 inches. In the proximal end of the body the 

 osseous lamellae springing from the sides of 

 the medullary cavity arch inwards towards the 

 centre, intersecting each other in a manner 

 comparable to the tracery of a Gothic window. 

 The lower wall of the neck is thick distally, near 

 the trochanter minor, but thins rapidly before 

 it reaches the head. From this aspect of the neck there spring a series of oblique lamellae 

 which pass proximally and upwards, spreading in fan-shaped manner into the under surface of 

 the head. These are intersected above by lamellae which arch medially from the lateral side of the 



CALCAR FEMORALE 



TROCHANTER 

 MINOR 



FIG, 279. SECTION THROUGH HEAD AND NECK OF 

 FEMUR TO SHOW CALCAR FEMORALE. 



